What type of lens corrects hyperopia (farsightedness)?
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Convex lens.
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What type of lens corrects hyperopia (farsightedness)?
Convex lens.
What do axons of neurons in the olfactory bulb project through?
The olfactory tract to the olfactory cortex or secondary olfactory areas.
What are the types of oblique muscles associated with the eye?
Superior and inferior oblique muscles.
What is the sclera?
The white outer layer of the eye.
What are the three layers of neurons in the neural layer of the retina?
Photoreceptor cells, bipolar cells, and ganglionic cells.
What type of vision do rods provide?
Black and white vision.
What structure do olfactory nerves project through to reach the olfactory bulb?
The foramina in the cribriform plate.
What is the macula?
A small yellow spot on the retina.
What are the three tunics that compose the wall of the eye?
Fibrous, vascular, and nervous tunics.
How do tears exit the lacrimal gland?
Through several lacrimal ducts.
What role does the lens play in vision?
It focuses light on the macula and fovea centralis.
What happens to tears after they pass over the surface of the eye?
They enter the lacrimal canaliculi.
What is the fovea centralis known for?
It is the area of greatest visual acuity with tightly packed photoreceptor cells.
What is the function of the nasolacrimal duct?
It drains tears from the eye into the nasal cavity.
What does the fibrous tunic of the eye consist of?
Sclera and cornea.
What is the function of the tip link in hair cells?
It attaches the tip of each stereocilium to the side of the next longer stereocilium.
How does light intensity affect color vision?
As light intensity decreases, our ability to see color also decreases.
What type of lens corrects myopia (nearsightedness)?
Concave lens.
Where do tears go after passing through the nasolacrimal duct?
They enter the nasal cavity.
What are the two main layers of the retina?
Pigmented retina and sensory retina.
What happens when stereocilia bend?
They open K+ gates (mechanically gated ion channels).
Where do axons from the thalamus terminate?
In the taste area of the insula.
What are the two chambers of the anterior compartment?
Anterior chamber (between cornea and iris) and posterior chamber (between iris and lens).
What is the far point of vision?
The point at which the lens does not have to thicken to focus, typically 20 feet or more from the eye.
What is the role of adenylate cyclase?
It catalyzes the conversion of ATP to cyclic AMP (cAMP).
What are taste buds?
Supporting cells surrounding taste (gustatory) cells.
Where are tears produced?
In the lacrimal gland.
What is the role of the olfactory cortex?
It is involved in the conscious perception of smell.
What is the optic disc?
The blind spot where blood vessels enter the eye and nerve processes exit.
What is the structure of the eye described as?
A hollow, fluid-filled sphere.
What separates the nuclear layers in the retina?
Plexiform layers.
What are the olfactory nerves formed by?
The axons of the olfactory neurons.
What occurs when an odorant binds to a specific odorant receptor?
It triggers a response in the olfactory hair.
What type of cells are found in the sensory retina?
Rod and cone cells sensitive to light.
What are the types of rectus muscles associated with the eye?
Superior, inferior, medial, and lateral rectus muscles.
Where are the cell bodies of afferent neurons grouped?
In the cochlear (spiral) ganglion.
What is the pathway of tears after entering the lacrimal canaliculi?
They are carried through the lacrimal sac to the nasolacrimal duct.
What happens to the gated ion channel in an unstimulated olfactory hair?
The gated ion channel is closed.
How many extrinsic eye muscles are attached to each eye?
Six.
What do afferent fibers form?
The cochlear nerve.
What is a hair bundle?
The stereocilia of one inner hair cell.
What is the function of the ossicles in the ear?
They transmit vibrations from the eardrum to the oval window.
What are cones responsible for?
Color vision and visual acuity.
What structures are included in the bony labyrinth?
Cochlea, vestibule, and semicircular canals.
What do the tufted and mitral cells extend to?
The olfactory tract.
Where is perilymph located?
In the spaces between the membranous labyrinth and the periosteum of the bony labyrinth.
What fills the vitreous chamber of the eye?
Jelly-like vitreous humor.
What is the function of vitreous humor?
Helps maintain intraocular pressure, holds lens and retina in place, and refracts light.
What process requires energy in the rhodopsin cycle?
Conversion of all-trans-retinal to 11-cis-retinal.
Where are the most sensitive receptors for salty taste located?
Tip of the tongue.
What is the function of the pigmented retina?
Helps to separate sensory cells and reduce light scattering.
What covers the basilar region of hair cells?
Synaptic terminals of sensory neurons.
What is the role of the external ear in hearing?
It collects sound waves and conducts them through the external auditory canal.
What is the role of the oval window?
It serves as the connection between the middle and inner ear.
What do ciliary glands do?
They are modified sweat glands that empty into hair follicles of the eyelashes.
What does the α subunit of the G protein activate?
Adenylate cyclase.
What does light cause retinal to change into?
All-trans-retinal.
What occurs when ions enter the olfactory hair?
Depolarization of the olfactory neuron.
What initiates the process of hearing in the middle ear?
The tympanic membrane vibrates, causing the ossicles to vibrate and transferring vibrations to the oval window.
What is the function of the pigmented layer of the retina?
Enhances visual acuity by isolating individual photoreceptors and reducing light scattering.
How does olfactory information reach the brain?
It goes directly to the olfactory cortex of the frontal lobe without passing through the thalamus.
What substances are associated with the sweet taste?
Sugars, some carbohydrates, and some proteins (e.g., NutraSweet: aspartame).
What does the α subunit of the G protein activate in the sweet taste pathway?
Adenylate cyclase, which produces cAMP.
How many olfactory neurons are present in the olfactory epithelium?
10 million olfactory neurons.
What is found at the medial canthus?
A caruncle with modified sweat and sebaceous glands.
What is the visual pigment found in cones?
Iodopsin.
What covers the lens?
An elastic, transparent capsule.
What is emmetropia?
The normal resting condition of the lens.
Where do ganglion cell axons converge?
At the optic disc.
What is the role of pupil constriction?
It varies the depth of focus.
What is the primary function of the external and middle ear?
Hearing.
What is the function of the inner ear?
Hearing and equilibrium.
What causes astigmatism?
Cornea or lens not uniformly curved.
What is the palpebral fissure?
The space between the eyelids.
What are eyelashes?
A double or triple row of hairs that protect the eyes.
What functions does aqueous humor serve?
Maintains intraocular pressure, supplies nutrients, and contributes to light refraction.
What do association neurons receive input from?
They also receive input from the brain.
What happens to rods in the absence of light?
They are depolarized.
What is a major dysfunction associated with diabetes?
Dysfunction of peripheral circulation.
What are the three divisions of the ear?
External, middle, and inner ear.
What does the external auditory canal produce?
Cerumen.
What is a cataract?
Clouding of the lens.
What fills the scala vestibuli and scala tympani?
Perilymph.
What happens to the nuclei and organelles in the lens?
They lose nuclei and other organelles.
What fills the anterior compartment of the eye?
Aqueous humor.
What is the conjunctiva?
A thin transparent mucous membrane covering the eye and inner surface of the eyelids.
How is aqueous humor produced and returned to circulation?
Produced by the ciliary process and returned through the scleral venous sinus.
What is the fovea centralis known for?
Highest visual acuity.
What G protein is activated by rhodopsin when light hits it?
Transducin.
What type of cells line the anterior surface of the lens?
Simple cuboidal epithelial cells.
What is hyperopia?
Farsightedness, where the image is focused behind the retina.
Where are Vallate papillae located?
Along the border between the anterior and posterior parts of the tongue.
What happens to the perilymph in the inner ear during hearing?
Vibration of perilymph causes the vestibular membrane to vibrate, which in turn causes vibrations in endolymph.
Where do sensory axons from the cochlear ganglion terminate?
In the cochlear nucleus in the brainstem.
What type of connective tissue makes up the sclera?
Dense collagenous connective tissue with elastic fibers.
What is the cochlear duct also known as?
Scala media.
What are the two types of muscles that control pupil size?
Sphincter pupillae (parasympathetic) and dilator pupillae (sympathetic).
What are the two types of hair cells in the inner ear?
Inner hair cells (responsible for hearing) and outer hair cells (regulate tension on the basilar membrane).
What mechanism do sugars use to cause depolarization in sweet taste receptors?
Sugars bind to receptors and activate a G protein mechanism.
Where is the olfactory epithelium located?
In the superior nasal cavity.
What protein changes shape when struck by light in rods?
Rhodopsin.
What are the two components that rhodopsin separates into when activated by light?
Opsin and retinal.
What is presbyopia?
Degeneration of accommodation, corrected by reading glasses.
What is glaucoma?
Increased intraocular pressure due to aqueous humor buildup.
What separates the middle ear from the inner ear?
The oval and round windows.
What is the second cochlear chamber called?
Scala tympani.
What is the significance of the cornea being avascular?
It allows for transparency and light entry without scattering.
What is the function of the iris?
Controls the amount of light entering the pupil.
What type of vibrations does the basilar membrane near the helicotrema respond to?
Low-frequency vibrations.
What are the hair-like projections on hair cells called?
Stereocilia.
Where are the most sensitive receptors for sweet taste located?
On the tip of the tongue.
What are the main components of the vision accessory structures?
The eyes, accessory structures, and optic nerves, tracts, and pathways.
Where does the foot of the stapes rest?
On the oval window, held in place by the annular ligament.
What are olfactory hairs?
Cilia of olfactory neurons embedded in mucus.
What do rods and cones synapse with?
Bipolar cells, which then synapse with ganglion cells.
What happens when the associated G protein is activated?
The α, β, and γ subunits dissociate.
What is the function of rods in vision?
Spatial summation.
What happens to the eyes as objects move close?
The eyes rotate medially in a reflex contraction of the medial rectus.
What is the structure of the lens?
Transparent and biconvex.
What happens to Na+ channels when cGMP concentration decreases?
They close.
What is the tympanic membrane?
A thin membrane of two layers of epithelium with connective tissue between.
How is sound detected in the inner ear?
The displacement of the basilar membrane is detected by hair cells.
Where are the tips of inner hair cells embedded?
In the tectorial membrane.
What is the taste that is craved by humans and caused by amino acids?
Umami (Glutamate).
What are canthi?
The points where the eyelids meet, including lateral and medial canthi.
What proteins accumulate in the lens?
Crystallines.
What occurs during accommodation?
Ciliary muscles contract, pulling the choroid toward the lens, reducing tension on suspensory ligaments, making the lens more spherical.
What are the types of papillae?
Filiform, Vallate, Foliate, and Fungiform.
What is the auricle or pinna made of?
Elastic cartilage covered with skin.
What is retinal detachment?
A condition that can result in complete blindness.
What is macular degeneration?
A condition common in older people, leading to loss in acute vision.
What do thalamic neurons project to in the hearing pathway?
The auditory cortex.
What is the first step in the pathways for the sense of taste?
Axons of sensory neurons synapse with taste receptors and pass through cranial nerves VII, IX, and X.
Where are cones most numerous?
In the fovea and macula lutea.
What is the primary function of the cochlea?
Hearing.
How many types of iodopsin are there and what do they respond to?
Three types that respond to blue, red, and green light.
What allows for the interpretation of millions of colors?
Overlap in response to light from the three types of cones.
What is the initial configuration of retinal in rhodopsin?
11-cis-retinal.
What produces the bitter taste sensation?
Alkaloids, which are toxic.
What functions do neurons in the superior olivary nucleus serve?
They send axons to the inferior colliculus, back to the inner ear, or to motor nuclei in the brainstem that send efferent fibers to the middle ear muscles.
How do sodium ions contribute to the sensation of salt taste?
They diffuse through Na+ channels, resulting in depolarization.
What are the three ossicles of the ear?
Malleus, incus, and stapes.
Where do the axons from the nucleus of the tractus solitarius synapse?
In the thalamus.
How do odorants interact with olfactory neurons?
Odorants dissolve in mucus and attach to receptors, causing cilia to depolarize and initiate action potentials.
Can one receptor respond to multiple types of odors?
Yes, one receptor may respond to more than one type of odor.
What are the two types of fluids found in the inner ear?
Endolymph and perilymph.
What condition is characterized by an abnormal increase in intraocular pressure?
Glaucoma.
What is myopia?
Nearsightedness, where the focal point is too near the lens, causing the image to be focused in front of the retina.
What are lens fibers?
Long, columnar epithelial cells found in the posterior region of the lens.
What is the most sensitive receptor location for sour taste?
Lateral aspects of the tongue.
What is the vascular tunic of the eye?
The middle layer containing most of the blood vessels and melanin.
What does the ciliary body produce?
Aqueous humor that fills the anterior chamber.
What is the function of eyebrows?
They shade the eyes and inhibit sweat.
What are the enlarged ends of the dendrites of olfactory neurons called?
Olfactory vesicles.
What is the tarsal plate?
A dense connective tissue layer that helps maintain the shape of the eyelid.
What is the function of the vestibule and semicircular canals?
Balance.
What is the pathway of olfactory sensory neurons?
Olfactory neurons pass through the cribiform plate to olfactory bulbs and synapse with tufted or mitral cells.
Where is endolymph found?
In the membranous labyrinth.
What is the near point of vision?
0 feet.
What type of cell receives input from numerous rods in the eye?
Bipolar cell.
What does cGMP phosphodiesterase do in the rhodopsin cycle?
Catalyzes the conversion of cGMP to GMP.
What are the primary functions of the sclera?
Maintains shape, protects internal structures, and provides muscle attachment points.
What is the choroid associated with?
It is associated with the sclera.
What type of photoreceptor is more sensitive to light than cones?
Rods.
What are the two types of conjunctiva?
Palpebral conjunctiva (inner surface of eyelids) and bulbar conjunctiva (anterior surface of the eye).
Where are tears produced?
In the lacrimal gland.
What effect does cAMP have on ion channels?
cAMP opens ion channels, such as Na+ and Ca2+ channels.
What type of cell receives input from several bipolar cells?
Ganglion cell.
Which type of papillae is most numerous but has no taste buds?
Filiform papillae.
Which type of papillae contains the most sensitive taste buds?
Foliate papillae.
What are the two main pathways that axons from the cochlear nucleus project to?
The superior olivary nucleus and the inferior colliculus.
How does the collagen fiber structure differ between the sclera and cornea?
Collagen fibers in the sclera are large and opaque, while in the cornea they are small and transparent.
What is the composition of the cornea's connective tissue matrix?
Contains collagen, elastic fibers, and proteoglycans.
What causes the tympanic membrane to vibrate?
Sound waves.
What is the function of the auditory or eustachian tube?
It opens into the pharynx and equalizes pressure.
What is the role of the cornea in the eye?
It is a transparent window that allows light to enter and bends and refracts light.
What is the role of the inferior colliculus in hearing?
Axons from the inferior colliculus project to the medial geniculate nucleus of the thalamus.
What is the wall of the scala vestibuli called?
Vestibular membrane.
What fills the cochlear duct?
Endolymph.
What is the role of ciliary muscles?
They control the shape of the lens.
What are the sensory cells in the spiral organ called?
Hair cells.
What is the function of the scala vestibuli?
It extends from the oval window to the helicotrema at the cochlear apex.
What type of vibrations does the basilar membrane near the oval window respond to?
High-frequency vibrations.
What does the scala vestibuli communicate with?
The scala vestibuli communicates with the cochlea.
How does the width of the basilar membrane change?
It increases from 0.04 mm near the oval window to 0.5 mm near the helicotrema.
